Deckle assembly for a paper making machine



Jan. 2, 1968 F. J. GEDEMER 3,361,620

DECKLE ASSEMBLY FOR A PAPER MAKING MACHINE Filed Dec. 11, 1964 /w mlioriUnited States Patent Office Fatented Jan. 2, 1965 3,361,620 DECKLEASSEMBLY FOR A RAPER MI SKING MACHINE Fred J. Gedemer, Appleton, Wisassignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis. FiledDec. 11, 1964, Ser. No. 417,707 11 Claims. ((13. 162-353) ABSTRACT OFTHE DISCLOSURE A paper machine having a deckle box over each edge of afourdrinier wire in close proximity to a stock discharge slice openingof a headbox, and each deckle box having a bottom and a pair oflaterally spaced side walls cooperating with the bottom to define apassage having an inlet facing the slice opening to collect a portion ofpaper stock from the edges of a thin layer of stock emerging under ahead of pressure from the headbox and divert this portion of stock up aslight incline and away from the wire in a downstream direction.

This invention relates to a paper making machine and in particular thatportion of a machine where paper stock is discharged from a headboxthrough a slice assembly and deposited upon a fourdrinier wire.

The quality of paper along the edges of a web formed on a fourdrinierwire is afl'ected by the pattern of stock flow both within the headboxand on the fourdrinier wire. Within the headbox the friction of stockflow on headbox walls, as well as distributor roll heads and journals,acts to slow the velocity of stock movement along the inner walls of theheadbox and tends to produce paper with light edges. To avoid thisproblem one form of prior art structure provided a drain along each sidewall of the headbox to draw oil such slower moving stock before itreached the slice. This solved the problem of light edges but caused aslight lateral cross flow of stock which can continue even after thestock has passed through the slice and is deposited upon the wire. Thecross flow of stock causes two problems. A first problem is that with across flow stock is taken away from the flow through the middle of theslice. A second problem is that the cross flow continuing beyond theslice strikes ruler deckles (which are walls closely spaced above eachedge portion of the wire) and causes a reflected wave back across thestock on the wire. These two problems can be solved but require acareful adjustment of the slice and ruler deckles that slope upwardlyaway from the wire so such wave energy can be dissipated by the waverolling up the slope of the deckle. Accordingly, it is an importantobject of the present invention to eliminate such slow moving edge stockin a new and improved manner without causing stock cross flow with theattendant need for such aforementioned slice adjustment and sloped rulerdeckles.

According to the present invention the slower moving edge stock is drawnaway from the main body of stock but not until after the stock haspassed out of the headbox through the slice. According to a preferredembodiment of the invention a deckle box is provided on each side of themachine. Each deckle box has a bottom, inboard and outboard side wallsand a cover defining an enclosed passage having an inlet opening facingthe slice. The box bottom rests firmly upon an apron projectingoutwardly beneath the slice. The bottom of the box is slightly inclinedupwardly in the direction away from the apron so it does not makecontact with the upper surface of the rapidly moving fourdrinier wire.Each box has a straight section diverging slightly away from theadjacent outer edge of the wire in a downstream direction and thisstraight section is long enough to reach from the inlet opening tobeyond the supporting structure. At the end of the straight section ofbox opposite the inlet opening, each box turns sharply outward and awayfrom the fourdrinier wire. The inboard wall and bottom of each box areeach contoured at the inlet opening to define a knife edge flush withthe outer surfaces thereof and upwardly inclined away from the slice. Asmall jet air shower may be aimed down the knife edge of the inboardwall to disperse any stock fiber that may collect on this edge. Aconventional ruler deckle may engage the inboard wall of each box at theinlet opening and extend parallel to the wire edge and part way alongthe length of the web forming surface of the wire. The ends of the rulerdeckles adjacent the inlet openings are contoured to provide a knifeedge flush with the inboard facing surface thereof to provide a smoothsurface merging with the inboard wall of each deckle box. Thus eachdecide box draws off the slower moving edge stock as it flows over theapron downstream of the slice and collects it in an unset condition thatcan be immediately recirculated back to stock mixing equipment, and thisis accomplished without causing any undesirable cross flow conditionswithin the headbox or on the fourdrinier wire.

.Other objects and how they are attained will appear from the followingmore detailed description of the invention with reference to thedrawings showing a perspective View of a portion of a paper makingmachine constructed according to the present invention.

Referring now to the drawing, there is shown a fourdrinier wire 10looped around a breast roll 11 that turns in the direction indicated byan arrow. A portion of a headbox is shown at 12 and the portion shownincludes part of a front wall structure 13 with an inclined dependingflexible upper lip 14. Part of a headbox bottom structure 15 is shownand this structure includes a lower lip 16 with an apron 17 extendingtherefrom. A blade 18 is mounted on the lateral edge of upper lip 14that cooperates with lower lip 16 to define an adjustable slice opening19. The slice opening 19 is adjusted by means (not shown) connected toupper lip 14- that are operative to bend the flexible upper lip 14 toadjust the slice opening 19.

A deckle box 20 is provided over each lateral edge of wire 1t) and apron17. Each box 20 has a bottom 21, inboard and outboard walls 22, 23,respectively, and a cover 24 to define an enclosed passage 25 having aninlet opening 26 facing the slice opening 19. The bottom 21 of each box20 rests firmly upon the apron 17. The bottom 21 is slightly inclinedupwardly in the direction away from apron 17 to avoid making contactwith the upper surface of the rapidly moving wire 10. Each box has astraight section diverging slightly away from the adjacent outer edge ofwire 10 in a manner most easily seen in the upper right hand portion ofthe drawing, and this straight section may be connected to supportingcolumns 3t) by means such as bolt assemblies 31. Beyond the supportingcolumns 3a the boxes 29 turn sharply outward away from the fourdrinierwire 10 and then turn downwardly to discharge to the pit (not shown)beneath wire 19. Other suitable provisions for recirculating stockpassing through boxes 20 may, of course, be made as desired.

The inboard wall 22 and bottom 21 of each box 20 are each contoured atthe inlet opening 26 to define a knife edge 32, 33 flush with the outersurfaces thereof and upwardly inclined away from the slice 19. A smallwater or air jet 34 may be aimed down the knife edge 32 of the inboardWall 22 to disperse any stock fiber that may collect on this edge. Aconventional ruler deckle 35 may engage and be fastened to the inboardwall 22 of each box at the inlet opening 26 and extend parallel to the 3wire edge and part way along the length of the web forming surface ofthe wire 10. The ends of the ruler deckles 35 remote from box 20 may befastened to support structure 37. The ends of the ruler deckles 35adjacent the inlet openings 26 are contoured to provide a knife edge 36flush with the inboard facing surface thereof to provide a smoothsurface merging with the inboard wall 22 of each deckle box 20.

In the operation of the described apparatus, dilute paper stock inheadbox 12 passes between upper and lower lips 14, 16 and out throughslice 19 to flow over the apron 17 and on to the rapidly moving wire 10.The slower moving portion of the stock flowing along the laterallyspaced edges of apron 17 will be directed by the knife edges 32, 33 toflow through inlet opening 26 and into the passage 25 within each decklebox 20. Stock passing between the knife edges 32 Will flow on to theWire 16 and be carried between the ruler deckles 35 in a conventionalmanner. However, each deckle box 20 draws oh the slower moving edgestock after it has passed out of the headbox 12 and this stock in afluid unset condition is collected for recirculation or disposal as maybe desired. This stock is drawn off apron 17 without causing anyundesirable cross flow conditions within the headbox 20 or on thefourdrinier wire 10. Although the stock is drawn off after emerging fromthe headbox, it is collected in an unset condition and therefore noadded energy is required to break up fibers before recirculating thestock. Further, if it is desired to make paper in a width that isnarrower than the maximum for which a machine is designed, the effectivewidth of the wire can be reduced by providing wider decide boxes or byplacing spacers (not shown) between the box walls 23 and supportingstructures such as the columns 30, to move the boxes 20 inwardly fromthe lateral edges of the screen 10.

From the foregoing it will be understood that the present invention ispossessed of unique advantages. However, such modifications andequivalents of the disclosed concepts such as readily occur to thoseskilled in the art are intended to be included within the scope of thisinvention and thus the scope of this invention is intended to be limitedonly by the scope of the claims such as are, or may hereafter be,appended hereto.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In a paper making machine including a fourdrinier wire and a headboxhaving a slice arranged to discharge stock from the slice on the wire,support structure along both sides of the wire and extending upwardlythereof, a deckle box over each edge of said wire and connected to saidsupport structure, each deckle box comprising a bottom and a pair oflaterally spaced sidewalls cooperating with said bottom to define apassage having an inlet opening facing said slice, and each said boxhaving a section diverging away from the adjacent edge of said wire in adownstream direction to divert the portion of paper stock collectedthrough said inlet from the edges of the thin layer of stock emergingfrom the slice opening of said headbox.

2. In a paper making machine including a fourdrinier wire and a headboxhaving an apron and a slice arranged to discharge stock from the sliceover the apron and onto the'wire, support structure along both sides ofthe wire and apron and extending upwardly thereof, and a vertical rulerdeckle parallel to and spaced inwardly of each edge of the wire with oneend thereof on said apron and the opposite end connected to said supportstructure, a deckle box over each edge of said wire outboard of saidruler deckle and connected to said support structure, each deckle boxcomprising a bottom resting upon said apron downstream of the slice anda pair of laterally spaced sidewalls cooperating with said bottom todefine a passage having an inlet opening facing said slice, and eachsaid box having a section diverging away from the adjacent ruler decklein a downstream direction to divert the portion of paper stock collectedthrough said inlet from the edges of the thin layer of stock emergingfrom the slice opening of said headbox.

3. In a paper making machine including a fourdrinier wire and a headboxhaving a slice arranged to discharge stock from the slice onto the wire,support structure along both sides of the wire and apron and extendingupwardly thereof, a deckle box over each edge of said wire and connectedto said support structure, each deckle box comprising a bottom and apair of laterally spaced sidewalls cooperating with said bottom todefine a passage having an inlet opening facing said slice, the inboardsidewall and bottom of each box defining a knife edge flush with theexternal surfaces of said box, and each said box having a sectiondiverging away from the adjacent edge of the wire in a downstreamdirection to divert the portion of paper stock collected through saidinlet from the edges of the thin layer of stock emerging from the sliceopening of saidheadbox.

4. In a paper making machine including a fourdrinier wire and a headboxhaving a slice arranged to discharge stock from the slice onto the wire,support structure along both sides of the wire and apron and extendingupwardly thereof, a deckle box over each edge of said wire and connectedto said support structure, each deckle box comprising a bottom and apair of laterally spaced sidewalls cooperating with said bottom todefine a passage having an inlet opening facing said slice with aperimeter sloped upwardly and away from said slice, the inboard sidewalland bottom of each box defining a knife edge flush with the externalsurfaces of said box, and each said box having a section diverging awayfrom the adjacent edge of the wire in a downstream direction to divertthe portion of paper stock collected through said inlet from the edgesof the thin layer of stock emerging from the slice opening of saidheadbox.

S. In a paper making machine including a fourdrinier wire and a headboxhaving an apron and a slice arranged to discharge stock from the sliceover the apron and onto the wire, support structure along both sides ofthe wire and apron and extending upwardly thereof, and a vertical rulerdeckle parallel to and spaced inwardly of each edge of the wire with oneend thereof on said apron and the opposite end connected to said supportstructure, a deckle box over each edge of said wire outboard of saidruler deckle and connected to said support structure, each deckle boxcomprising a bottom resting upon said apron downstream of the slice anda pair of laterally spaced sidewalls cooperating with said bottom todefine a passage having an inlet opening facing said slice with aperimeter sloped upwardly and away from said slice, the inboard sidewalland bottom of each box defining a knife edge flush with the externalsurfaces of said box, and each said box having a section beginning atsaid inlet diverging away from the adjacent ruler deckle in a downstreamdirection to position the knife edge on the inboard wall in a commonvertical plane with the inboard vertical surface of said adjacent rulerdeckle.

6. In a paper making machine including a fourdrinier wire and a headboxhaving an apron and a slide arranged to discharge stock from the sliceover the apron and onto the wire, support structure along both sides ofthe wire and apron and extending upwardly thereof, and a vertical rulerdeckle parallel to and spaced inwardly of each edge of the wire with oneend thereof on said apron and the opposite end connected to said supportstructure, a deckle box over each edge of said wire outboard of saidruler deckle and connected to said support structure, each deckle boxcomprising a bottom resting upon said apron downstream of the slice andsloping upwardly in a downstream direction, anda pair of laterallyspaced sidewalls cooperating with said bottom to define a passage havingan inlet opening facing said slice with a perimeter sloped upwardly andaway from said slice, the inboard sidewall and bottom of each boxdefining a knife edge flush with the external surfaces of said box, andeach said box having a section beginning at said inlet diverging awayfrom the adjacent ruler deckle in a downstream direction to position theknife edge on the inboard wall in a common vertical plane with theinboard vertical surface of said adjacent ruler deckle.

7. A deckle box for diverting and collecting a portion of paper stockalong an edge of a thin layer emerging from the slice opening of aheadbox, the deckle box comprising a bottom and a pair of laterallyspaced sidewalls defining a passage having an inlet opening, at leastone of said sidewalls defining a knife edge flush with the externalsurfaces thereof to divert a flow over said edges inwardly of theperimeter of said inlet.

8. A deckle box for diverting and collecting a portion of paper stockalong an edge of a thin layer emerging from the slice opening of aheadbox, the deckle box comprising a bottom and a pair of laterallyspaced sidewalls defining a passage having an inlet opening, at leastone of said sidewalls and said bottom each defining a knife edge flushwith the external surfaces thereof to divert a flow over said edgesinwardly of the perimeter of said inlet.

9. A deckle box for diverting and collecting a portion of paper stockalong an edge of a thin layer emerging from the slice opening of aheadbox, the deckle box comprising a bottom and a pair of laterallyspaced sidewalls defining a passage having an inlet opening with aperimeter sloped upwardly toward a portion of said passage remote fromsaid inlet, at least one of said sidewalls and said bottom each defininga knife edge flush with the external surfaces thereof to divert a flowover said edges inwardly of the perimeter of said inlet.

11). A deckle box for diverting and collecting a portion of paper stockalong an edge of a thin layer emerging from the slice opening of aheadbox, the deckle box comprising a bottom and a pair of laterallyspaced sidewalls defining a passage having an inlet opening, one of saidside walls defining a knife edge flush with the external surfacesthereof to divert a flow over said edges inwardly of the perimeter ofsaid inlet, and said box having a section that diverges away from theside of said box having a sidewall defining a knife edge.

11. A deckle box for diverting and collecting a portion of paper stockalong an edge of a thin layer emerging from the slice opening of aheadbox, the deckle box comprising a bottom and a pair of laterallyspaced sidewalls defining a passage having an inlet opening with aperimeter sloped upwardly toward a portion of said passage remote fromsaid inlet, one of said sidewalls and said bottom each defining a knifeedge flush with the external surfaces thereof to divert a flow over saidedges inwardly of the perimeter of said inlet, and said box having asection beginning at said inlet that diverges away from the side of saidbox having a sidewall defining a knife edge.

References Cited UNITED STATES PATENTS 1,734,929 11/1929 Vedder 162-353X DONALL H. SYLVESTER, Primary Examiner. S. LEON BASHORE, Examiner. A.C. HODGSON, Assistant Examiner.

